The common types of skin cancer, basal cell epitheliomas and squamous cell carcinomas are produced by chronic exposure to ultraviolet irradiation. Heat has been conclusively shown to increase the adverse effects of both acute and chronic ultraviolet irradiation. The present series of experiments have been designed to determine the influence of wind velocity and humidity on both the acute and chronic effects of ultraviolet irradiation, including carcinogenesis. To our knowledge these factors have not been previously studied under controlled conditions. The present series of experiments are being conducted in two environmental chambers specifically designed for such experiments. The chambers provide thermostatically controlled temperature ranging from 40 degrees fahrenheit to 120 degrees fahrenheit; humidity variability from 10 to 100%; and fans that can alter wind velocity from 0-16 mph. Westhinghouse FS-40 T-12 sunlamps are mounted within the chambers and are controlled by a timing device. In the first 2 years of this grant, we have shown conclusively that wind increases the adverse effects of acute and chronic ultraviolet injury. Humidity experiments have been conducted but the data to date is inconclusive.